This circuit for testing old analog lines was published in April 1986 Radio Electronics magazine. The circuit uses only passive components.
This filter has the components calculated for the frequency of 1 kHz but can be changed. The input...
This capacimeter was obtained in European documentation from the 1980s. The indicator instrument, a...
This circuit was found in the Optoelctronics Sourcebook from Texas Instruments. The circuit has a...